Grading house GradeKC has put together this video showcasing some of their work for the movie, The House on Pine Street. It's a fascinating insight into the affect grading can have on the look of a film.

Director Jeffrey Zablotny has a good insight into the process.

"The ‘original picture quality’ that appears bland and tonally even—that’s not really representative of what’s captured by the camera; it’s just the most neutral possible picture to show all data available to the colourist. (It’s the equivalent of a RAW file.) There’s actually a tremendous amount of contrast and shape already built into that captured image by the cinematographer on set, and typically his or her intention is carried out and subtly enhanced by the colourist. It’s tempting to conclude that digital colour grading is the magic wand that truly brings the image to life, but it’s actually the last step of a long creative chain that begins before shooting even starts.The versions of the shots you’re seeing fly by aren’t finished potential iterations, but more like important milestones as the grade progresses —hopefully, the cinematographer’s intent is the always final one. There’s an initial pass or two for overall balance and temperature (often called primary colour correction), secondary passes for subtler tonal values (subtly making things greener, bluer, etc), and then final cosmetic passes for vignetting, and special details. This video chooses not to address the wonderful world of keying and windows, which allow extremely particular details of the image (just one face, or whites of the eyes, or perhaps a certain specific shade of red in a lamp somewhere) to be isolated and tracked. Incredible technology."

It's a great primer on the grading process, there's more before and after stuff over at GradeKC's website too.